Acute Closed Angle Glaucoma

Question 1

Pathophysiology for acute closed angle glaucoma

Answer 1

Iris bulges forward and seals off the trabecular meshwork from the anterior chamber preventing aqueous humour from being able to drain away

This leads to a continual build-up of pressure

Question 2

Risk factors for acute closed angle glaucoma

Answer 2

• Increasing age
• Females 4: 1 Males
• Family history
• Chinese and East Asian ethnic origin.
• Shallow anterior chamber
• Hypermetropic

Question 3

Which medication can precipitate acute angle-closure glaucoma

Answer 3

• Adrenergic medications e.g. noradrenalin
• Anticholinergic medications e.g. oxybutynin and solifenacin
• Tricyclic antidepressants e.g. amitriptyline

Question 4

Presentation of acute angle-closure glaucoma

Answer 4

• Severely painful red eye
• Blurred vision
• Halos around lights
• Associated headache, nausea and vomiting

Question 5

Onset of acute angle-closure glaucoma

Answer 5

Sudden

Question 6

Examination of acute angle-closure glaucoma

Answer 6

• Red-eye
• Teary
• Hazy cornea - blue corneal hue indicating oedema
• Decreased visual acuity
• Fixed dilated oval pupil

Question 7

Initial management of acute angle-closure glaucoma

Answer 7

Medical emergency

Referred for same-day assessment by an ophthalmologist.

Pilocarpine 4% brown eyes 2% blue eyes

Acetazolamide

Laser peripheral iridotomy

Question 8

If there is a delay in admission, whilst waiting for an ambulance

Answer 8

Lie patient on their back without a pillow

Give pilocarpine eye drops (2% for blue, 4% for brown eyes)

Give acetazolamide 500 mg orally

Given analgesia and an antiemetic if required

Question 9

Pilocarpine moa

Answer 9

Acts on the muscarinic receptors in the sphincter muscles in the iris -constriction of the pupil (miotic agent).

Ciliary muscle contraction.

Cause the pathway for the flow of aqueous humour from the ciliary body, around the iris and into the trabecular meshwork to open up.

Question 10

Acetazolamide moa

Answer 10

Carbonic anhydrase inhibitor - reduces the production of aqueous humour

Question 11

Secondary Care Management of closed angle glaucoma

Answer 11

Pilocarpine

Acetazolamide (oral or IV)

Hyperosmotic agents - glycerol or mannitol

Timolol - beta-blocker

Dorzolamide - carbonic anhydrase

Brimonidine -sympathomimetic

Laser iridotomy - definitive treatment

Question 12

Mannitol

Answer 12

Increase the osmotic gradient between the blood and the fluid in the eye

Question 13

Timilol

Answer 13

Beta blocker that reduces the production of aqueous humour

Question 14

Dorzolamide

Answer 14

Carbonic anhydrase inhibitor

Reduces the production of aqueous humour

Question 15

Brimonidine

Answer 15

Sympathomimetic

Reduces the production of aqueous fluid and increases uveoscleral outflow

Question 16

Laser iridotomy

Answer 16

Laser to make a hole in the iris to allow the aqueous humour to flow from the posterior chamber into the anterior chamber.

Relieves pressure that was pushing the iris against the cornea and allows the humour to drain.

Question 17

Post trabeculectomy complications

Answer 17

Blebitis
Iriritis
Sudden increase/decrease in intra ocular pressure
Endophthalmitis